Date: Sun, 7 Jul 2002 11:19:32 +0100 From: Matthew Seaman <m.seaman@infracaninophile.co.uk> To: Darren Pilgrim <dmp@pantherdragon.org> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: OpenSSH v3.4_p1 sshd exits on signal 11? Message-ID: <20020707101932.GA20900@happy-idiot-talk.infracaninophi> In-Reply-To: <3D279634.EEBDBE6B@pantherdragon.org> References: <3D279634.EEBDBE6B@pantherdragon.org>
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On Sat, Jul 06, 2002 at 06:15:32PM -0700, Darren Pilgrim wrote: > I'm running openssh v3.4_p1 without privelege seperation enabled, and > I'm getting a strange problem. When I first start sshd, I can log in > without problems, everything is fine. But then I log out, and after a > time try to log back in and the connection fails giving me this error > in /var/log/messages: Is that the openssh-portable port, or openssh from a recent -STABLE? Privilege separation is disabled by default in -STABLE because it interferes with certain authentication mechanisms like opie. If you're not using those mechanisms then you should certainly turn privsep on. > /kernel: pid 87512 (sshd), uid 0: exited on signal 11 Ouch. That's certainly not meant to happen. Your process died from a segmentation violation --- trying to read memory outside what the kernel has permitted the process to use. There should be a sshd.core file around somewhere. If you can find that file you can in theory use gdb(1) to extract a stack trace and find out exactly what was going on when the process died, but that won't do you much good unless you've got a version of the sshd binary with debug symbols still in place. > I'm not sure how much time between logins if required for this to > occur. I does happen when I try to log in after having been logged out > overnight, though. You can turn up the logging level of the sshd daemon by changing the LogLevel value in sshd_config(5). A level of DEBUG3 will give you a practically blow-by-blow account of everything the sshd does. Warning: it will create *lots* of output, and it may well reveal what should be private information about other users. Now for two complete stabs in the dark at why this is happening to you. i) What CFLAGS setting are you using in /etc/make.conf? If it's any higher optimization than: CFLAGS= -O then you will likely see weird effects, like processes dieing for no apparent reason. If you want to squeeze maximum performance out of your box, note that `-O' optimization already gives you all the most effective stuff, and that setting CPUTYPE appropriately has a much more useful effect. ii) Do you possibly have a hardware problem --- bad memory stick or the like? In that case, you'ld see SEGVs from all sorts of processes, not just sshd. It's particularly noticable if you work your box hard, by doing a buildworld, say. Try a few passes of memtest86 (http://www.memtest86.org) to see if it can pick any problems up. Try pulling out each memory stick in turn and running on reduced memory for a few hours to see if that isolates the problem. Cheers, Matthew -- Dr Matthew J Seaman MA, D.Phil. 26 The Paddocks Savill Way Tel: +44 1628 476614 Marlow Fax: +44 0870 0522645 Bucks., SL7 1TH UK To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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